JP2018189427A - Gas sensor device, gas sensor system, and gas sensor device manufacturing method - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a gas sensor device capable of, when detecting a detection target gas such as ammonia, detecting the detection target gas with high selectivity without the influence of gas exempt from a detection target, which changes an electric resistance value of a contacted part on the same principle as the detection target gas.SOLUTION: A gas sensor device includes: first and second electrodes; and a connected part which is electrically connected to the first and second electrodes, and which is a polythiophene film absorbing cuprous bromide.SELECTED DRAWING: Figure 1

Description

  The present invention relates to a gas sensor device, a gas sensor system, and a method for manufacturing the gas sensor device.

  Research and development is being carried out to detect diseases at an early stage without subjective symptoms by detecting specific chemical substances contained in human breath. When the contacted part of the semiconductor formed on the electrode is exposed to the measurement target gas, the detection target gas is detected by utilizing the property that the electrical resistance value of the contacted part changes due to contact with the detection target gas. Gas sensor devices are known. By using such a gas sensor device, a simple test is performed by detecting a gas indicating a disease included in exhaled breath.

  In order to detect a specific detection target gas from a measurement target gas in which a plurality of gases are mixed, for example, detection is performed at a ratio of about 100 times or more with respect to other gases (non-detection target gas) included in the measurement target gas A gas sensor device having a high gas type selectivity and showing a response of an electric resistance value change to a target gas is used. As a gas sensor device exhibiting high ammonia gas selectivity, for example, a device using cuprous bromide is known (see, for example, Non-Patent Document 1).

Analytica Chimica Acta Vol. 515 (2004) p. 279-284

  Among the non-detection gases included in the measurement target gas, there are those that contact the contacted part in the same way as the detection target gas and change the electrical resistance value of the contacted part slightly compared to the detection target gas. To do. The detection target gas selectivity of the gas sensor device is lowered by the non-detection target gas that contacts the contacted portion and changes the electric resistance value, and the detection target gas cannot be accurately quantified.

  In one aspect, an object of the present invention is to provide a gas sensor device with improved detection target gas selectivity.

  In one aspect, the gas sensor device includes a first electrode and a second electrode, and a polythiophene film that is electrically connected to the first electrode and the second electrode and adsorbs cuprous bromide.

  In one aspect, a gas sensor system comprises a gas sensor device comprising a first electrode and a second electrode, and a polythiophene film that is electrically connected to the first electrode and the second electrode and adsorbs cuprous bromide; A measurement unit for measuring the electrical characteristics of the polythiophene film.

  In one aspect, the gas sensor device manufacturing method forms a polythiophene film that is electrically connected to the first electrode and the second electrode and adsorbs cuprous bromide.

  As one aspect, a gas sensor device and a gas sensor system with improved detection target gas selectivity can be obtained.

  As one aspect, a gas sensor device with improved detection target gas selectivity can be manufactured.

FIG. 1 is a cross-sectional view of a gas sensor device according to a first embodiment. FIG. 2 is a top view of the gas sensor device according to the first embodiment. FIG. 3 is a diagram illustrating a polythiophene plane of the gas sensor device according to the first embodiment. FIG. 4 is a diagram showing a polythiophene stacking structure of the gas sensor device according to the first embodiment. FIG. 5 is a diagram illustrating a molecular structure of a contacted part of the gas sensor device according to the first embodiment. FIG. 6 is a diagram illustrating a molecular equilibrium state in a contacted portion that is expected when the gas sensor device according to the first embodiment is in contact with a gas. FIG. 7 is a diagram illustrating a process of the method for manufacturing the gas sensor device according to the first embodiment. FIG. 8 is a diagram illustrating a process of the method for manufacturing the gas sensor device according to the first embodiment. FIG. 9 is a diagram illustrating a process of the method for manufacturing the gas sensor device according to the first embodiment. FIG. 10 is a diagram illustrating a process of the method for manufacturing the gas sensor device according to the first embodiment. FIG. 11 is an X-ray diffraction profile obtained by measuring the gas sensor device manufactured by the gas sensor device manufacturing method according to the first embodiment. FIG. 12 is a scanning transmission electron microscope image of the gas sensor device manufactured by the gas sensor device manufacturing method according to the first embodiment. FIG. 13 is a diagram illustrating a gas sensor system according to the second embodiment. FIG. 14 is a response profile of the gas sensor device according to the second embodiment with respect to ammonia gas and hydrogen sulfide gas having an atmospheric concentration of 1 ppm. FIG. 15 is an enlarged view showing an initial response from the start of exposure to the target gas in the response profile shown in FIG. 14 until 30 seconds. FIG. 16 is a diagram illustrating an expired gas sensor system according to the third embodiment. FIG. 17 is a response profile of the gas sensor device according to the comparative example with respect to ammonia gas and hydrogen sulfide gas having an atmospheric concentration of 1 ppm. FIG. 18 is an enlarged view showing the initial response from the start of exposure to the target gas in the response profile shown in FIG. 17 until 60 seconds. FIG. 19 is a diagram illustrating a modification of the gas sensor device according to the first embodiment. FIG. 20 is a diagram illustrating a modification of the gas sensor device according to the first embodiment.

  Hereinafter, a gas sensor device, a gas sensor system, and a method for manufacturing the gas sensor device according to the embodiment of the present invention will be described with reference to FIGS. However, the technical scope of the present invention is not limited to these embodiments, but extends to the matters described in the claims and equivalents thereof. Note that even if the drawings are different, corresponding parts are denoted by the same reference numerals, and description thereof is omitted.

  Hereinafter, the gas sensor device according to the first embodiment will be described with reference to FIGS. The gas sensor device according to the first embodiment shows a response with a change in electric resistance value with respect to contact with a detection target gas in the measurement target gas. The measurement target gas of the gas sensor device according to the first embodiment is, for example, human breath, and the detection target gas is ammonia gas.

  FIG. 1 is a cross-sectional view of a gas sensor device according to a first embodiment. FIG. 2 is a top view of the gas sensor device according to the first embodiment. As shown in FIGS. 1 and 2, the gas sensor device 10 includes a substrate 11, two electrodes 12 a and 12 b, and a contacted portion 13.

  The substrate 11 is, for example, a silicon wafer with a thermal oxide film having a side of 15 mm (thermal oxide film thickness: 100 nm).

  The two electrodes 12a and 12b are provided on the substrate 11 as a first electrode 12a and a second electrode 12b. The two electrodes 12a and 12b have, for example, a width of 5 mm, a length of 6 mm, and a film thickness of 60 nm. The two electrodes 12a and 12b are provided at a predetermined interval, for example, 1 mm.

  The contacted portion 13 is a polythiophene film 14 that is electrically connected to the two electrodes 12a and 12b and adsorbs cuprous bromide. The contacted part 13 is, for example, a rectangle having a film thickness of 60 nm and a side of 5 mm.

  The polythiophene film 14 is composed of a plurality of polythiophene molecules and forms a stacking structure in which the thiophene rings of the plurality of polythiophene molecules are stacked in the direction from the first electrode 12a to the second electrode 12b. The detection target gas is preferably detected from the point that the detection target gas can be detected with high response sensitivity. The plurality of polythiophene molecules may be stacked in an inclined state with respect to the direction from the first electrode 12a to the second electrode 12b.

  It is preferable that the polythiophene film 14 has a highly conductive polythiophene as a p-type semiconductor because the detection target gas can be detected with high response sensitivity when the detection target gas is detected using the gas sensor device 10. A specific material of polythiophene included in the polythiophene film 14 is, for example, poly (3-hexylthiophene) (PH3T).

  For example, cuprous bromide may be physically adsorbed on the polythiophene film 14 and may be present at a distance where electrons can be exchanged with the polythiophene molecules of the polythiophene film 14. For example, cuprous bromide may be chemisorbed by forming a coordination bond on the polythiophene film 14 to form a coordinate bond with the polythiophene molecule of the polythiophene film 14. Cuprous bromide has copper (I) ions and bromide ions.

  FIG. 3 is a diagram illustrating a polythiophene plane of the gas sensor device according to the first embodiment. As shown in FIG. 3, the polythiophene film 14 has a repeating unit of polythiophene having a thiophene ring. The atoms constituting the thiophene ring contained in the repeating unit of polythiophene are present on the same plane 14A (polythiophene plane 14A).

  FIG. 4 is a diagram showing a polythiophene stacking structure of the gas sensor device according to the first embodiment. As shown in FIG. 4, the polythiophene film 14 may include a plurality of polythiophene molecules having a stacking structure in which a polythiophene plane 14A and another polythiophene plane including the polythiophene plane 14B are stacked. A plurality of polythiophene molecules are stabilized in a stacking structure by π-π interaction.

  Cuprous bromide is adsorbed on the side of the stacking structure polythiophene. Cuprous bromide is exposed near the surface of the contacted portion 13 by adsorbing to the side of the stacking structure polythiophene. Since the detection target gas easily comes into contact with cuprous bromide, the gas sensor device 10 exhibits high response sensitivity to the detection target gas.

  As described above, the gas sensor device 10 including the contacted portion 13 that is the polythiophene film 14 that has adsorbed cuprous bromide is highly sensitive in response to a change in electric resistance value with respect to contact with ammonia gas that is a detection target gas, Since the response of the electric resistance value change to the contact with the hydrogen sulfide gas which is a gas not to be detected becomes low sensitivity, high ammonia gas selectivity is exhibited.

  Hereinafter, an expected operation principle of the gas sensor device according to the first embodiment will be described with reference to FIGS.

  FIG. 5 is a diagram illustrating a molecular structure of a contacted part of the gas sensor device according to the first embodiment. Cuprous bromide and polythiophene form a coordination bond by donating electrons to cuprous bromide from the sulfur atom of the thiophene ring included in polythiophene.

  FIG. 6 is a diagram illustrating a molecular equilibrium state in a contacted portion that is expected when the gas sensor device according to the first embodiment is in contact with a gas. When ammonia as the detection target gas approaches and comes into contact with the contacted portion 13, it donates electrons to the cuprous bromide and forms a coordinate bond. When the coordinate bond between ammonia and cuprous bromide is formed, the coordinate bond between polythiophene and cuprous bromide is broken.

  When the coordination bond between polythiophene and cuprous bromide is broken, the electrons donated to the cuprous bromide are returned to the polythiophene film 14. Since the p-type carrier concentration of the polythiophene film 14 decreases, the electrical resistance value of the contacted portion 13 increases.

  When the ammonia concentration in the measurement target gas exposed to the contacted portion 13 increases, a coordinate bond between ammonia and cuprous bromide is formed as shown by the right arrow in FIG. On the contrary, when the ammonia concentration in the measurement target gas exposed to the gas sensor device 10 decreases, a coordinate bond between polythiophene and cuprous bromide is formed as shown by the left arrow in FIG.

  The gas sensor device 10 is coordinated between ammonia and cuprous bromide by a reaction of coordination bond formation from the molecular equilibrium in the contacted part 13 according to the ammonia concentration in the measurement target gas to be exposed. The ratio of the bond formation is changed, and the response of the electric resistance value change is shown.

  Since the ability of ammonia to form a coordination bond with cuprous bromide is much higher than the ability of polythiophene to form a coordination bond with cuprous bromide, in contacted part 13 exposed to ammonia gas. Immediately, the coordination bond between polythiophene and cuprous bromide is broken, and the coordination bond between ammonia and cuprous bromide is formed. Since the gas sensor device 10 exposed to the ammonia gas immediately increases the speed of forming a coordinate bond between ammonia and cuprous bromide, detection by a response to a change in electric resistance value is highly sensitive.

  On the other hand, the ability of hydrogen sulfide to form a coordination bond with cuprous bromide is similar to the ability of polythiophene to form a coordination bond with cuprous bromide. In part 13, the coordination bond breakage between polythiophene and cuprous bromide takes longer than the coordination bond breakage between polythiophene and cuprous bromide in contacted part 13 exposed to ammonia gas. The gas sensor device 10 exposed to hydrogen sulfide gas is hindered by the coordination bond between polythiophene and cuprous bromide, and the rate of forming the coordination bond between hydrogen sulfide and cuprous bromide is difficult to increase. The detection by the response of the change in the electric resistance value becomes low sensitivity.

  Hereinafter, the manufacturing method of the gas sensor device concerning 1st Embodiment is demonstrated with reference to FIGS.

  In the method for manufacturing a gas sensor device according to the first embodiment, a first electrode and a second electrode are formed on a substrate, a polythiophene film electrically connected to the first electrode and the second electrode is formed, and a polythiophene film is formed. By contacting cupric bromide, a contacted portion that is a polythiophene film adsorbing cuprous bromide is formed.

  FIG. 7 is a diagram illustrating a process of the method for manufacturing the gas sensor device according to the first embodiment. On the substrate 11, two electrodes 12a and 12b are formed as shown in FIG. The substrate 11 is, for example, a silicon wafer with a thermal oxide film having a side of 15 mm (thermal oxide film thickness: 100 nm). The two electrodes 12a and 12b are, for example, gold electrodes having a width of 5 mm, a length of 6 mm, and a film thickness of 60 nm, and are formed by vacuum deposition with an interval of 1 mm.

  FIG. 8 is a diagram illustrating a process of the method for manufacturing the gas sensor device according to the first embodiment. A polythiophene film 14 electrically connected to the two electrodes 12a and 12b is formed. The formation of the polythiophene film 14 is performed, for example, by applying 1 μL of a P3HT solution dissolved in o-dichlorobenzene at a concentration of 1% by weight to a rectangle having a side of 5 mm and drying it naturally. This is preferable because the yield of the polythiophene film 14 is increased, and a gas sensor device capable of detecting the detection target gas with high response sensitivity can be obtained.

  FIG. 9 is a diagram illustrating a process of the method for manufacturing the gas sensor device according to the first embodiment. Cupric bromide is brought into contact with the polythiophene film 14. In order to contact cupric bromide, for example, a 0.1 mol / L methanol solution of cupric bromide is dropped and left for 5 minutes, then washed with pure methanol and naturally dried. .

  Copper (II) ions contained in the cupric bromide oxidize the polythiophene film 14 to receive electrons from the polythiophene film 14 and are reduced to copper (I) ions. By the oxidation-reduction reaction, cuprous bromide is formed and adsorbed on the polythiophene film 14.

  FIG. 10 is a diagram illustrating a process of the method for manufacturing the gas sensor device according to the first embodiment. As shown in FIG. 10, a contacted portion 13 that is a polythiophene film 14 that adsorbs cuprous bromide is formed, and the gas sensor device 10 is manufactured.

  As described above, the method of manufacturing the gas sensor device that forms the contacted portion 13 that is the polythiophene film 14 that is electrically connected to the first electrode 12a and the second electrode 12b and adsorbs cuprous bromide is ammonia gas. The gas sensor device 10 with improved selectivity can be manufactured.

  Elemental analysis by X-ray photoelectron spectroscopy (XPS) is performed on the gas sensor device 10 manufactured by the method for manufacturing a gas sensor device according to the first embodiment. When the elemental composition ratio analysis by XPS is performed on the surface of the polythiophene film 14 to which cuprous bromide is adsorbed at an analysis target depth of about 5 nm, the number of copper atoms, the number of bromine atoms, the number of sulfur atoms in the contacted part 13 The ratio of the number of carbon atoms is about 1: 1: 13: 130.

  The analysis depth is about 5 nm with respect to the film thickness of 60 nm of the polythiophene film 14. From the ratio of the number of carbon atoms and the number of sulfur atoms, one copper atom is present on the surface of the polythiophene film 14 with respect to 13 thiophene rings. Is included in the ratio. Moreover, the observed copper atom is in an ionic state, and the ratio of monovalent ions to divalent ions is estimated to be about 10: 1. Therefore, most of the copper compound adsorbed on the polythiophene film 14 is cuprous bromide.

  FIG. 11 is an X-ray diffraction profile obtained by measuring the gas sensor device 10 manufactured by the gas sensor device manufacturing method according to the first embodiment. As shown in FIG. 11, only the peak derived from the stacking structure of P3HT, which is the material of the polythiophene film 14, is observed. Since no peak indicating cuprous bromide is observed, it is expected that a cuprous bromide crystal of at least several nm is not formed.

  FIG. 12 is a scanning transmission electron microscope image of the gas sensor device 10 manufactured by the gas sensor device manufacturing method according to the first embodiment. The crystal structure of cuprous bromide is not observed.

  As a result of the analysis, the gas sensor device 10 manufactured by the first embodiment of the gas sensor device manufacturing method is mainly composed of P3HT, which is the material of the polythiophene film 14, and cuprous bromide grows crystals on the surface of the P3HT. It is presumed that the structure exists in a discrete manner without causing it.

  Hereinafter, the gas sensor system according to the second embodiment will be described with reference to FIG. The gas sensor system according to the second embodiment is a gas sensor system that detects a detection target gas in a measurement target gas. The measurement target gas of the gas sensor system according to the second embodiment is, for example, human breath, and the detection target gas is ammonia gas.

  FIG. 13 is a diagram of a gas sensor system according to the second embodiment. As shown in FIG. 13, the gas sensor system 20 includes the gas sensor device 10 and a measurement unit including a measurement unit 21 and a calculation unit 22.

  The measurement unit 21 is electrically connected to the two electrodes 12 a and 12 b of the gas sensor device 10 and measures the electrical characteristics of the contacted portion 13 of the gas sensor device 10. The measurement unit 21 is a measurement circuit such as an electrometer, for example. For example, the measuring unit 21 applies a constant potential to both ends of the contacted part 13 and the resistor connected in series, and measures the potential of the contact point between the contacted part 13 and the resistor, thereby measuring the contacted part 13. Measure the electrical resistance. For example, the measuring unit 21 applies a constant potential to both ends of the contacted part 13 and measures the current value of the contact of the contacted part 13.

The calculation unit 22 calculates a change in electrical characteristics of the contacted part 13 of the gas sensor device 10. The calculation unit 22 is electrically connected to the measurement unit 21, receives a measurement value of the electric characteristic of the gas sensor device 10 measured by the measurement unit 21, and calculates a change in the electric characteristic. The calculation unit 22 is a control device such as a computer, for example. The change in the electrical characteristics is, for example, the ratio or difference between the electrical resistance initial value R ₀ of the contacted portion 13 and the electrical resistance value R after a lapse of a certain period. The change in electrical characteristics is, for example, the ratio or difference between the initial current value of the contacted portion 13 and the current value after a lapse of a certain period. The calculation unit 22 may calculate the concentration of the detection target gas based on the calculated change in electrical characteristics.

For example, the calculating unit 22 records the electrical resistance value of the contacted part 13 measured by the measuring unit 21 once every second, and sets the electrical resistance value before exposure to the measurement target gas as the electrical resistance initial value R _0. For example, a change per hour with respect to the electric resistance initial value R ₀ may be calculated for the electric resistance value R after a certain period from the start of exposure to the target gas, for example, 10 seconds later.

  The calculation unit 22 is a profile of change in electrical characteristics of the contacted part 13 over time, for example, a change in electrical resistance value of the contacted part 13 over time, which is created by exposing the gas to be detected with a gas having a known concentration to the gas sensor device 10. May be created and recorded, and the concentration may be calculated by comparing the calculated change in electrical resistance value per hour with the recorded profile.

  The calculation unit 22 is based on a change in electrical characteristics for a certain period from the start of exposure of the gas to be measured to the gas sensor device 10, for example, a change per hour in the electrical resistance value in a period until a response to hydrogen sulfide is started. The gas concentration may be calculated.

  As described above, the gas sensor system 20 including the gas sensor device 10, the measurement unit 21, and the calculation unit 22 includes the gas sensor device 10 that exhibits high ammonia gas selectivity. it can.

  Hereinafter, the response of the electrical resistance value change to ammonia and hydrogen sulfide having a concentration of 1 ppm in the gas sensor system according to the second embodiment will be described with reference to FIGS. 14 to 15.

  The gas sensor device 10 is installed in an air flow, and the electrical resistance value of the gas sensor device 10 with respect to ammonia is measured with respect to ammonia by alternately exposing clean air and ammonia having a concentration of 1 ppm. Similarly, the gas sensor device 10 is installed in an air flow and alternately exposed to clean air and hydrogen sulfide having a concentration of 1 ppm, thereby measuring the electric resistance value of the gas sensor device 10 with respect to hydrogen sulfide over time.

FIG. 14 is a response profile of the gas sensor device according to the second embodiment with respect to ammonia gas and hydrogen sulfide gas having an atmospheric concentration of 1 ppm. The horizontal axis represents time, and the vertical axis represents relative response intensity. The relative response intensity is a ratio between the electric resistance initial value R ₀ of the gas sensor device 10 under clean air and the electric resistance value R measured every second. The greater the relative response intensity changes with time, the more sensitive the gas sensor device 10 is to the gas in response to changes in electrical resistance.

  As shown in FIG. 14, the gas sensor device 10 has a large change per hour in relative response intensity due to contact with ammonia. On the other hand, when the gas sensor device 10 is brought into contact with hydrogen sulfide, the relative response intensity does not change greatly for 300 seconds from the start of exposure. Since the gas sensor device 10 responds with high sensitivity to ammonia and responds with low sensitivity to hydrogen sulfide, the ammonia gas selectivity of the gas sensor device 10 is high.

  FIG. 15 is an enlarged view showing an initial response from the start of exposure to the target gas in the response profile shown in FIG. 14 until 30 seconds. As shown in FIG. 15, the response of the gas sensor device 10 to hydrogen sulfide has no significant change in relative response intensity for 30 seconds from the start of exposure. Since the formation of coordination bond between hydrogen sulfide and cuprous bromide is inhibited by the coordination bond between polythiophene and cuprous bromide, the response start of the electrical resistance value to hydrogen sulfide of gas sensor device 10 is delayed. It is to become.

  By utilizing the delay in the start of the response of the gas sensor device 10 to hydrogen sulfide and using the electrical resistance value during the period from the start of exposure to the gas to be measured to the start of the response to hydrogen sulfide, hydrogen sulfide is used. Accurate quantification of ammonia can be performed without the influence of. This is apparent from the delayed response start of the gas sensor device 10 to hydrogen sulfide as compared to a comparative example described later.

  Hereinafter, the expired gas sensor system according to the third embodiment will be described with reference to FIG. The expired gas sensor system according to the third embodiment detects ammonia gas in human expired air. Ammonia gas contained in exhaled breath is known to be a marker gas indicating Helicobacter pylori infection associated with gastric cancer and heart disease. By using the breath gas sensor system according to the third embodiment, a simple test for early detection of diseases such as cancer can be performed.

  FIG. 16 is a diagram illustrating an expired gas sensor system according to the third embodiment. As shown in FIG. 16, the expired gas sensor system 30 includes a gas sensor device 10, a measurement unit 21, a sensor unit 31 having a transmission unit 33, a reception unit 34, a calculation unit 22, and an output unit 35. And a monitor unit 32.

  The sensor unit 31 is a housing that houses the gas sensor device 10, has a blow-in port and an exhaust port, and can introduce exhaled breath exposed to the gas sensor device 10. The sensor unit 31 may include, for example, a sensor that measures temperature, humidity, and atmospheric pressure, and another gas sensor device that uses a gas other than ammonia gas as a detection target gas.

  From the measurement start time, the measurer blows exhaled air into the housing of the sensor unit 31 for a certain period of time through the air inlet. The time for blowing the breath into the sensor unit 31 is, for example, 15 seconds.

  The transmission unit 33 transmits the electrical characteristics of the gas sensor device 10 measured by the measurement unit 21 from the measurement start time once per second to the monitor unit 32 having the reception unit 34 via wireless communication.

  The calculation unit 22 calculates and calculates an electrical characteristic of a certain period, for example, a change per hour in the electrical resistance value of the contacted part 13 of the gas sensor device 10 from the time point 4 seconds after the measurement start time to the time point 13 seconds later. Based on the change of the electrical resistance value per time, the ammonia gas concentration is calculated and used as the calculation result. The calculation unit 22 stores a calibration curve prepared in advance and indicating a change in the electric resistance value of the gas sensor device 10 corresponding to the ammonia gas concentration, and contrasts the calculated change in the electric resistance value per hour with the calibration curve. Then, the ammonia concentration may be calculated.

  The output unit 35 outputs the calculation result calculated by the calculation unit 22. The output unit 35 is, for example, a display or a speaker.

  As described above, an exhalation gas sensor including the gas sensor device 10, the sensor unit 31 including the measurement unit 21, and the transmission unit 33, the reception unit 34, the calculation unit 22, and the monitor unit 32 including the output unit 35. The system can accurately and easily measure the ammonia gas concentration in the exhaled gas.

  Hereinafter, the gas sensor device according to the comparative example will be described. Compared to the first embodiment, description of common elements is omitted.

  The gas sensor device according to the comparative example includes a contact portion of cuprous bromide instead of the contact portion that is the polythiophene film adsorbing cuprous bromide of the first embodiment.

  Hereinafter, the operation principle of the gas sensor device according to the comparative example will be described.

  When ammonia as the detection target gas comes into contact with the contacted part 13, it donates electrons to the cuprous bromide to form a coordinate bond. When electrons are donated from the ammonia to the cuprous bromide, the p-type carrier concentration of the cuprous bromide decreases, so that the electrical resistance value of the contacted portion 13 increases.

  Hereinafter, the response of the electrical resistance value change with respect to ammonia and hydrogen sulfide having a concentration of 1 ppm in the gas sensor device according to the comparative example will be described with reference to FIGS. 17 to 18. The change with time of the electric resistance value of the gas sensor device according to the comparative example is measured by the same method as that of the gas sensor system according to the second embodiment.

  FIG. 17 is a response profile of the gas sensor device according to the comparative example with respect to ammonia gas and hydrogen sulfide gas having an atmospheric concentration of 1 ppm. FIG. 18 is an enlarged view showing the initial response from the start of exposure to the target gas in the response profile shown in FIG. 17 until 60 seconds. The response intensity of the gas sensor device 10 to hydrogen sulfide increases at a rate of about 1/10 of the response to ammonia. The start of response of the gas sensor device 10 to hydrogen sulfide is simultaneously with the start of response to ammonia.

  Hereinafter, the manufacturing method of the gas sensor device concerning a comparative example is demonstrated. Compared to the first embodiment, description of common elements is omitted.

  Instead of forming the polythiophene film of the first embodiment, the gas sensor device manufacturing method according to the comparative example forms a copper film electrically connected to the first electrode and the second electrode, The contacted part of cuprous bromide is formed by contacting the copper.

  In FIG. 8, instead of the polythiophene film 14 of the first embodiment, a copper film having a side of 5 mm and a film thickness of 60 nm is provided at a position electrically connected to the two electrodes 12 a and 12 b on the substrate 11 of the gas sensor device 10. , Using a mask.

  A cupric bromide solution is brought into contact with the formed copper film. The cupric bromide solution is washed with pure methanol after a 0.1 mol / L aqueous solution is dropped and immersed for 1 minute.

  In FIG. 10, the contact portion 13 of cuprous bromide is formed instead of the contact portion 13 which is the polythiophene film 14 adsorbing cuprous bromide of the first embodiment, and the gas sensor device 10 is manufactured. .

  The gas detection method by the gas sensor device and the gas sensor system according to the embodiment of the present invention is an example, and an optimal method is selected according to the detection target gas and the environmental conditions to be used.

  FIG. 19 is a diagram illustrating a modification of the gas sensor device according to the first embodiment. As shown in FIG. 19, the contacted portion 13 may be formed in contact with only the side surfaces of the two electrodes 12a and 12b, for example.

FIG. 20 is a diagram illustrating a modification of the gas sensor device according to the first embodiment. The contacted portion 13 may have any shape as long as it is electrically connected to the two electrodes 12a and 12b. For example, as shown in FIG. 20, it may be circular.

The polythiophene film in the first embodiment may be a single polythiophene molecule.

DESCRIPTION OF SYMBOLS 10 Gas sensor device 11 Board | substrate 12 Electrode 13 Contacted part 14 Polythiophene film | membrane 14A, 14B Polythiophene plane 20 Gas sensor system 21 Measurement part 22 Calculation part 30 Exhalation gas sensor system 31 Sensor part 32 Monitor part 33 Transmission part 34 Reception part 35 Output part

Claims (8)

A first electrode and a second electrode;
A gas sensor device comprising: a polythiophene film electrically connected to the first electrode and the second electrode and adsorbing cuprous bromide.   The gas sensor device according to claim 1, wherein the polythiophene film includes a polythiophene molecule, and the cuprous bromide is bonded to a sulfur atom included in the polythiophene molecule.   The gas sensor device according to claim 1, wherein the polythiophene film has a stacking structure in which a plurality of polythiophene molecules are stacked in a direction from the first electrode to the second electrode.   The gas sensor device according to claim 1, wherein the polythiophene film includes poly (3-alkylthiophene). A gas sensor device comprising: a first electrode; a second electrode; and a polythiophene film that is electrically connected to the first electrode and the second electrode and adsorbs cuprous bromide;
A gas sensor system comprising: a measurement unit that measures electrical characteristics of the polythiophene film.   Furthermore, the gas sensor system of Claim 5 provided with the calculation part which calculates the change of an electrical property using the electrical property measured by the said measurement part. A method of manufacturing a gas sensor device, wherein a polythiophene film that is electrically connected to a first electrode and a second electrode and adsorbs cuprous bromide is formed.   8. The method of manufacturing a gas sensor device according to claim 7, wherein the polythiophene film adsorbing the cuprous bromide is formed by bringing cupric bromide into contact with the polythiophene film.